Portable pressure fluid actuated tool



Nov. 16, 1937. E. H. sHAFF PORTABLE PRESSURE FLUID ACTUATED TOOL Filed0G11. 21, 1955 I l i Il QN um QN my WN @FQ Q hw QN hun@ Inwen-Jrov5779s/ H6770/ im ,Mz m m AT-m9; Nays Illu Patented Nov. 16, l1937lPORTABLE PRESSURE FLUID ACTUATED Iroor.

Ernest H. Sham.

Grand Haven, to William H. Keller, Inc., Grand Haven,

Mich., assignor Mich.,

a corporation of Michigan l Application October 2.1, 1933, Serial No.694,525 -l 13 Claims. (Cl. 121-34) The invention pertains to a pressureiiuid actuated tool and more particularly to a tool embodying a rotaryvpneumatic motor, such for example, as a portable grinder.

The primary object. of the invention is to provide a tool of the lightin weight, eflieient in operation'and which is strong and durable.

A further object isl to provide for effective lubrication of the variousworking parts of the tool through a utilization of the air pressure inthe tool for conveying and distributing lubricant to diierent parts ofthe tool.

Another object isto provide an improved construction for the motortending 'to reduce the wear on the blades of the rotor and also insuringthat the motor shall be capable of starting without manual assistance asis required in the 'case of the tools now on the market.

Still another objectof the invention is to provide a novel toolstructure of advantageous character, capable of easy assembly, andpermitting adjustability of the motor casing of the tool with respect tothe handle portion to vary the direc- D tion of discharge of theexhausting pressure uid.

The objects of the invention thus generally stated, together with otherand ancillary advantages, are attained by the construction andarrangement shown by way of illustration in the accompanying drawingwhich:

Figure 1 is a fragmentary vertical longitudinal sectional view throughmy improved tool taken substantially on line I-I of Fig. 3.

Fig. 2 is a fragmentary longitudinal sectional view through the handleportion of the tool, taken approximately in the plane of line 2--2 ofFig. 1 butwith the parts in a different relation.

Fig. 3 is a transverse sectional view taken in the plane of line 3-3 ofFig. 1.

Fig. 4 is a fragmentary transverse sectionall view taken in the plane ofline 4--4 of Fig. 1.

Fig. 5 is a fragmentary longitudinal sectional view approximately online 5--5v of Fig. 3 and. illustrating certain of the air passages forconveying lubricant to the interior of the motor.

Fig. 6 is a side elevational view of the motor cylinder.

Fig. 7 is an enlarged, exaggerated sectional view taken in the plane ofline 1--1 of Fig. 2.

My improved tool comprises a rotary pressure iiuid motor of theeccentrically walled chamber type. having a cylinder 8 comprising anelongated annular member providing a rotor chamber with a smooth innerbearing suriace'a and closed at character indicated which isv formingpart hereof, in-

plates 9 and I0, a' rotorill I2 and mounted on a opposite ends by endhaving a plurality of blades spindle I3 extending axially through therotor and carrying in the present instance, a grinding wheel I4. Thetool has anelongated body providing an annular casing I5 enclosing themotor, an elongated housing I6 of reduced diameter at one end of saidcasing in which the spindle is journaled, and a handle portion I1 at theother end of the casing with a governor chamber I8 formed between thehandle portion and the motor i casing. In the-present instance, thehandle portion I1 is tubular in form and is adapted for connection atits outer end with a source of air under pressure. This handle portionis equipped with a conventional manually operable valve device I9, andiiow of pressure fluid to the motor is also controlled `bya governorvalve 20 operating automatically to maintain a predetermined speed ofrotation of the spindle.

The motor cylinder 8 is mounted eccentrically within the casing I5 asshown clearly in Fig. 3, whereas the rotor II is mounted concentricallyof the casing I5 and coaxially of the spindle I3. Accordingly, the rotoris disposed eccentrically with respect to its cylinder 8, with one sideof the rotor in sliding Contact side of the latter. At its opposite endsthe rotor slidably engages with the end plates 9 and Ill which arecircular in form and abut the opposite ends of the annular memberforming the cylindrical side wall of the cylinder 8.

The spindle I3 is inserted through an axial bore I3il in the rotor II,the latter being held against rotation relative to the spindle by meansof the usual key 2I. At opposite ends of the rotor the spindle isjournaled in roller bearings 22 and with the cylinder at one 23,respectively, carried by heads 24 and 25 screw- A threaded into theopposite ends of an annular member or sleeve 26 and into abuttingrelation to the cylinder end plates 9 and Ill.v The ends of the sleeveare for this purpose extended beyond the end plates which lit snuglywithin the sleeve. Thus it will be observed that the heads 24 and 25coact with the sleeve 26 to form the motor casing` I5.

Cooperating with the end plates 9 and I0 of L by means of a dowel pin 29(Fig. 4), and the end plate I0 is also suitably held againstrotation bymeans of a dowel pin 30 (Fig. 6). A screw 3| entered through the casingsleeve 26 and into a notch 32 in the end plate 9 serves to hold thecylinder 8 against rotation in the casing I5.

The spindle housing I6 is formed integral with the head 24 of the motorcasing, and at its outer end is equipped with an antifriction bearing 33supporting the outer end of the spindle. The extreme outer end of thehousing is provided with a suitable packing gland 34 to prevent theescape of lubricant delivered to the housing in a manner hereinafter setforth.

Cast integrally with the head 25 at the opposite end of the motor casingis the handle portion I1 and governor chamber I8. The handle portion isequipped at its outer end with a nipple 35 for connection with a sourceof air under pressure, and within the handle portion is a valve casing36 providing a seat for a ball-Valve 31 pressed by means of a spring 38in the direction of such seat. Slidable within the casing 36 is a valveoperating stem 39 adapted for actuation by a hand lever 40 extendingthrough a slot 4l)a in the valve casing 36 and pivoted at 4I in thehandle portion, the latter being slotted for this purpose. As shown inFig. 2, the valve casing 36 cooperates with the handle portion to formpassages 42 'extending along opposite sides of the casing and openinginto the inner end of the handle portion beyond the valve casing.

The governor chamber I8 has its inner wall formed by the head 25 of themotor casing, the arrangement being such that the bearingE 23 mounted inthe head is exposed to the interior of the chamber. To complete thechamber, an annular wall 43 extends away from the head and thenceinwardly where it is united with the inner end of the handle portion.Centrally of this wall is an axial bore coaxial with the spindle andcontaining the valve 2D. Comprising the latter is a valve casing 44screw threaded into said bore. The interior of this casing communicatesthrough slots 45 with an annular chamber 46 encircling the valve casing44 and communicating with the motor cylinder by way of a passage 41extending longitudinally through the chamber in the wall 43 thereof.

'I'he spindle I3 extends through the bearing 23 into the governorchamber I8 and has pivotally mounted thereon fly-weights 48 having theirinner ends adapted to engage with the head 49 of a valve member 5D whichis slidable in the valve casing 44. The opposite end 5I of this Valvemember is movable into and out of closing relation to the slots 45 ofthe valve casing 44 to control the pressure fluid to the passage 41, itbeing observed that the end 5I of the valve member 50 is exposed to theaction of air under pressure tending to move the valve in an openingdirection, and that the fly-weights 48 revolving with the motor spindleoperate against such pressure to position the valve member so as tomaintain the speed of the tool substantially constant.

Air under pressure delivered by the passage 41 is introduced into themotor cylinder by a duct 52 formed in the rib 2l' on the motor cylinderand connected with the passage 41 by a port 53 in the end plate 9 and anannular groove 41a in the inner face of the head 25. Leading from theduct 52 into the cylinder are a plurality of ports 54 (Fig. 3) which itwill be observed discharge into the cylinder at one side of the rotorand at a. location adjacent the pointvof contact of the rotor with thecylinder wall. 'I'he motor fluidA is discharged from the cylinderthrough two sets of slots 55 and 56 opening into the casing I 5 near theopposite side of the rotor from the inlet ports 54, these two sets ofslots 55 and 56 being spaced apart circumferentially of the cylindersubstantially in accordance with the spacing of the rotor blades. Thisarrangement permits complete ex-A haustion of the motor fluid andprevents any possible back pressure dut to high speed operation.

It is common practice in motors of this type to bevel the outer edges ofthe rotor blades so that while these blades are being subjected to theaction of the pressure fluid in producing motor action, the bladesengage with the cylinder with a line contact, it having been found thatthis construction improves the operation of the motor. Such bevelling ofthe blades, however, requires a special machining operation andfurthermore requires that the blades be inserted in a certain way, whichis objectionable because of the possibility that they may through errorbe improperly inserted reversely from. that intended.

To obviate this diiculty while still providing for a line contactbetween the bla/des and the cylinder, the blades in my improved motorare inclined somewhat from a true radial position as shown Clearly inFig. 3, and this in the direction of rotation as indicated by the arrow.'I'he outer edges of the blades may accordingly be formed square andstill provide, through the medium of the trailing edge of the blade, aline contact with the inner or bearing surface of the cylinder.Accordingly, the manner in which the blades are inserted is immaterial,the possibility of error being thus removed.

Also, by reason of the inclination of the blades the motive fluid actingon the pressure side ,of the blade tends to counteract the tendency ofthe blade to move outward under the action of centrifugal force, thusreducing the wear on the blade. This is due to the fact that centrifugalforce acts away from the center of rotation and through the center ofgravity of the rotor I I, while the fluid pressure is at right angles tothe surface of the blades I2. Therefore the pressure on the inclinedblades I2 is at an acute angle against the direction of the centrifugalforce, whereby the uid pressure tends tol counteract the centrifugalforce and thereby relieve some pressure of the blades against the wallof the cylinder 8. In the discharge positions of the blades, the linecontact above referred to is of no consequence, and in such positionsthe outer edges of the blades engage with the cylinder throughout alarger surface area thereby minimizing the wear on the blades and on thecylinder. Wear is also minimized in the dischargel positions of theblade through having the blades at an angle in the rotor since the axisof the blades is at an acute angle relative to the direction of movementof the blades and the pressure of the blades against the cylinder walldue to centrifugal force is therefore reduced.

Diiculty is often experienced in tools of this type on account of thefailure of the tool to start where centrifugal force alone is dependedupon to hold the blades outwardly in the rotor and against the cylinder.For example, with the parts of the'tool in the relation shown in Fig. 3,the force of gravity would when the tool is idle, tend to move theactive blade on the side adiacent the inlet ports 54 inwardly to thebottom of its slot thereby rendering ineffective the admission of motiveiluid to the cylinder.

To overcome this objection, I haveprovided. in the inner faces of theend plates 8 and III of the cylinder, annular grooves 51 and 58positioned eccentrically with respect to the rotor axis as shown in Fig.4. For cooperation with these grooves, lugs 59 are formed ony theopposite ends of the blades I2, adapted to engage with the innerperipheral surfaces of the grooves when the motor is idle, so that whenthe motor comes to rest with the parts in a position corresponding tothat of Fig. 3, the active blade is'held outwardly and in position torespond to the introduction of motive iiuid. `'I'he grooves, it will beobserved, are made substantially wider than the lugs and in the normaloperation of the tool, the lugs are held clear of the inner walls of thegrooves by the action of centrifugal force. Also, they are preventedfrom engaging with the outer walls of the grooves by the bearingengagement between the blades and the inner peripheral wall of thecylinder.

An important feature of my invention has to do with the adequatelubrication of the working parts of the tool so as to reduce wear to aminimum as well as to improve the efficiency of the tool. Inaccomplishing this result, I utilize the governor chamber as a means forsupplying a suitablelubricant, preferably in the nature of a grease, thewall 43 of the governor chamber being provided for this purpose with aconventional grease fitting 60- facilitating the introduction of thelubricant into the chamber. Because of the position of the bearing 23 atone side of the chamber I8, this bearing is of course adequatelylubricated. To provide lubrication for the bearings 22 and 33 atopposite ends of the spindle housing, I providel a passage 6I axially ofthe spindle. This passage opens at one end into the 1 'chamber I8, andat its other end discharges through a diametricalduct 62 into theinterior of the spindle housing, the internal diameter of which issomewhat larger than the spindle. The chamber I8 is constantly` underair pressure due to the leakage of air escaping past the governor valve50 which has a sufficiently loose t, as shown in much exaggerated format5I]a in Fig. 7, to permit a limited leakage, and by venting this airpressure into the spindle housing, the lubricant in the chamber I8 isconveyed to the spindle housing I6 and hence to the bearings 23 and 33.

To lubricate the interior or bearing surface 8 of the motor cylinder aradial duct 63 is provided in the outer face of the end plate I0 (see`Fig. 5) which duct terminates at its inner end at the surface of thespindle as it passes plate. At its outer end the duct 63 communicateswith a port 64 near the peripheral edge of the end plate andregistering` with a passage 65 formed in the rib 28 protruding from theouter surface of the cylinder 8. The inner end of the passage 65connects by means of a port 66 through the bearing surface Iln with theinterior of the cylinder, so that air pressure escaping from the spindlehousing I6 along the spindle and through the bearing 22 enters theradial duct 63 and finds its way by means of the passage 65 and port 66into the cylinder. This air current carries with it a quantity of greasewhich is distributed throughout the cylinder by mean-s of the blades I2of the rotor. Preferably the port 66 opens into the cylinder between theexhaust ports 55 and 56 and in the area in which the blades I2 contactthe cylinder surface 8 with the greatest pressure in the course ofoperation due to thecombined centrifugal and inward forces acting on theblades dura quantity of through this enelv ing the returnmovementfthereof.` 'Thus, the lubricant becomes immediately useful whereit will be of greatest benefit.

It has been found that by this construction, it is only necessary tointroduce lubricant into the governor chamber and to the interior of themotor.

To permit the discharge of the exhausting air from the casing I5, aplurality of arcuate slots 61 are provided in the wall of the casingbetween the ,ribs 21 and 28 (Fig. 3). These slots are disposed oppositethe exhaust slots 56 in the cylinder but the air exhausting through theslots 55 of the cylinder is permittedto pass externally around thecylinder owing to the fact that the rib 28 does not extend throughoutthe length of the cylinder, as indicated in Figs. 5 and 6.

In the use of tools of this character, it is desirable that the positionof the exhausting slots 61 in the outer casing be capable of beingchanged with respect to the handle portion I1 according to varypermitsair under pressure delivered by passage .41 to issue to duct 52regardless of the relative position of the communicating openings of thepassage and duct due to the adjustment of the motor casing.

To reduce the weight of the tool, the spindle housing I6 and the head 24integral therewith, and the handle portion II together with the head 25and governor chamber, are preferably constructed of aluminum. The sleeve26, however, is constructed of steel to provide more effectiveprotection to the motor.

It will be observed that I have provided a tool of a very practicalcharacter, which is efiicient in operation and is capable of starting atall times from a position of rest. A high degree of durability is alsoobtained, and the parts are capable of being assembled and disassembled;the usual fastening bolts or screws are eliminated; the motor casing andhandle portion are capable of relative adjustment to suit varyingconditions; and a strong tool of minimum weight is assured.

I claim as my invention:

l. A portable tool having a rotary pneumatic I8 from whence it isconveyed. and efiectually distributed to the spindle bearings motor, atool spindle driven by the motor and eX- ber, and means for venting tothe interior of the motor air pressure escaping past said valve memberinto the governor chamber.

2. A portable tool having a rotary pneumatic motor, a tool spindledriven by the motor and extending axially therethrough, an elongatedbody providing an annular motor casing and an elongated housing at oneend of the motor casing having bearings for said spindle, and a handleportion at the opposite end of the motor casing with a chamber betweenit and the -handleportion adapted to contain a quantity of lubricant,valve controlled means for supplying pressure to the motor including avalve member projecting' blades movable outwardly from the rotor bycen-.

trifugal action in the rotation of the rotor, said cylinder having endwalls providing grooves concentric With the cylinder, and said bladeshaving means thereon extending into said grooves and operable in theidle position of the tool to prevent movement of the blades from aprojected position inwardly into the rotor, said grooves being of acontour and width to provide a clearance between said means and theouter peripheral walls of the grooves throughout operative movement ofthe rotor.

4. A pressure uid actuated tool' having a motor of the eccentricallywalled chamber type, comprising a cylinder having opposite end walls, arotor mounted eccentrically in said cylinder and having a plurality ofblades movable outwardly from the rotor by centrifugal action in therotation of the rotor, means operable in the idle position of the toolto prevent movement of the blades from a projected position inwardlyinto the rotor, said means including a part on each of said blades and agroove in one end wall of a width to provide a continuous clearancebetween said part on the blade and the inner and outer walls of thegroove in the normal operation of the tool.

5. A portable tool having a rotary pneumatic motor including a cylinder,a rotor mounted eccentrically in said cylinder and adapted to be rotatedby the force of fluid pressure, apair of passages in the Walls of saidcylinder, one of said passages communicating with a source of pressurefluid and having ports communicating with the interior of said cylinderto direct the pressure fluid into operative engagement with said rotor,and the other of said passages communieating with a source of lubricantand having a port to the interior of said cylinder to direct lubricantto said rotor.

6. A portable tool having a rotary pneumatic motor including a cylinderand a rotor mounted upon a tool spindle extending through said cylinder,an elongated body providing an annular motor casing, an elongatedhousing of reduced diameter at one end of the motor casing havingbearings for said spindle, a handle portion at the opposite end of themotor casing with a chamber between said motor and the handle portionadapted to contain a quantity of lubricant valve controlled means forsupplying air under' pressure to the motor and including a valveprojecting into said chamber, means for venting from said chamber to thespindle housing air pressure escaping past said valve into the chamberand including a passage formed in said spindle and communicating withsaid spindle housing, and a passage in the Wall of said cylindercommunicating with said spindle housing and the interior of thecylinder.

'7. A pressure fluid actuated tool having a rotary motor including acylinder and a rotor in said cylinder, a sleeve encircling the cylinderin eccentric relation thereto, ahead connected with one end of thesleeve and providing a. laterally offset fluid supply passage, saidcylinder having an inlet port arranged to communicate with said passageand a discharge port opening into the interior of said sleeve, saidsleeve having a discharge port permitting lateral escape of exhaustedpressure fluid therefrom, a handle portion rigid with said head andhaving valve-controlled means for supplying motive fluid to saidpassage, means closing the end of the sleeve opposite said head andactingto clamp the cylinder against the head in various positions ofcircumferential adjustment of the sleeve relative to the head whereby topermit a Variation in the position of said discharge port in the sleeverelative to said handle portion, and a flow passage connecting saidinlet port and said passage for providing an uninterrupted flow ofpressure fluid from said passage to said inlet port regardless of theadjusted position of the sleeve and the head.

8. A pressure fluid actuated tool having an elongated cylindricalcasing, comprising a sleeve having heads closing the ends thereof, and arotary motor of the eccentrically walled chamber type rigid within saidsleeve between said heads and having a cylinder comprising an annularthin-walled member 'of a length substantially less than said sleeve, anda pair of spaced longitudinal ribs on said cylinder for defining theposition of the latter eccentrically in said sleeve, said ribs havingpassages extending partially therethrough from opposite ends and incommunication with the interior of the cylinder.

9. A pressure fluid actuated tool having an elongated cylindricalcasing, comprising a sleeve and heads at the ends of said sleeve, arotary motor of the eccentrically walled-chamber type including a thincylinder comprising an annular member shorter than said sleeve andsecured between said heads, a longitudinal rib on said cylinder forsupporting the latter in said sleeve in eccentric relation thereto, aneccentric rotor rotatably mounted within said cylinder, dischargeopenings formed in the wall of said cylinder on opposite sides of saidrib, and exhaust openings in said sleeve, said rib being shorter thansaid cylinder, and providing a passage for the escape of pressurefromthe openings on both sides of said rib through said exhaust openings.

l0. A pressure uid actuated tool having a rotary motor of theeccentrically walled chamber type comprising a rotor and a plurality ofblades mounted for movement outwardly relative to the rotor and acylinder disposed eccentrically of the rotor and providing an innersurface adapted to be engaged by the outer edges of said blades, each ofsaid blades being inclined from a radius of the rotor in the directionof rotation thereof and having edge faces substantially perpendicular tothe side faces of the blade so as to provide relatively sharp trailingedges engageable with the inner surface of the cylinder in the projectedpositions of the blades, a chamber for containing grease to lubricatethe tool, means defining a passage from said chamber to said innersurface of the cylinder and providing a port opening to the interior ofthe cylinder through said surface, a passage for conducting pressurefluid to the interior of the cylinder for actuating said blades andmotor, and means providing communication between said chamber and saidpressure fluid passage so that grease will be forced from the chamber tothe interior of the cylinder through said rst mentioned passage tolubricate said surface and said blades and minimize wear as said sharptrailing edges move at high speed over the surface.

11. A portable pressure fluid actuated tool comprising, in combination,means housing a motor of the eccentrically walled chamber type includingan internally cylindrical Wall having a smooth inner surface and a rotorhaving a pluvrality of blades disposed for'movement outwardly sage todeliver lubricant under pressure to said blades.

12. A portable pressure uid actuated tool comprising, in combination,means enclosing a motor including an internally cylindrical wall havinga smooth inner surface and an eccentricaliy mounted rotor having aplurality of blades disposed for movement outwardly relative to therotor for engagement with said surface upon rapid rotation of saidrotor, a valve controlled passage in said means communicating at one endwith a source of pressure fluid and at its other end opening throughsaid surface to the interior of said motor for creating an operativepressure condition therein, a lubricant chamber near one end of saidrotor and having therein one end of a governor valve, the other end ofsaid valve projecting into a part of said passage to govern the flow ofpressure fluid therethrough, said valve being relatively loosely fittedand thereby permitting the restricted escape of pressure fluid from saidpassage `into said chamber to establish a pressure condition therein, alubricant passage leading from said chamber to said cylindrical surfacefor conveying lubricant under pressure from said chamber, and a port insaid surface establishing communication with said lubricant passage andspaced from the point at which said valve controlled passage opens intothe motor, the position of said port being such that lubricant underpressure is delivered to said blades in the area in which the bladescontact said surface with greatest pressure in the course of operation.

13. A pressure fluid actuated tool, including a rotary motor comprisingVan internally cylindrical smooth surface wall having circumferentiallyspaced sets of inlet and outlet ports, a r0- tor of smaller diameterthanthe inner diameter of said wall and mounted on an eccentric axis with aportionA of its periphery in sliding abutment with said wall betweensaid sets of ports, and a plurality of blades mounted in said rotor formovement outwardly relative to the rotor near the inlet ports andinwardly near the outlet ports so as to follow the inner surface of saidwall, each of said blades being inclined from a radius of the rotor inthe direction of rotation thereof and having an outer edge facesubstantially perpendicular to the side faces of the blade, theinclination and circumferential spacing of said blades being such thatthe sharp trailing edge of each of their edge faces engage said innersurface of the wall with a line contact while the blades are movingoutwardly and the outer edge faces contact said surface throughout alarger area while the blades are moving inwardly near said outlet ports,and means for supplying lubricant to said surface in the region in whichsaid blades are moving inwardly, whereby to relieve said blades fromwear due to the combined centrifugal and inward pressure acting on theblades during the return movement.

ERNEST I-I` SHAFF.

